16 U.S. Code § 438 - Repairs and improvements; how made

Any and all repairs, improvements, changes, and alterations in the grounds, buildings, and other appurtenances to the reservation shall be made only according to detailed plans which shall be approved by the Secretary of the Interior, and all such repairs, improvements, or alterations shall be made at the expense of the United States, and all such improvements, together with the reservation itself, shall become and remain permanently the property of the United States.